This invention relates to a tandem master cylinder device for hydraulic brake systems in motor vehicles, the device being particularly designed to produce a difference in output liquid pressure between a liquid chamber connected to a front brake and a liquid chamber connected to a rear brake by means of a liquid pressure control valve housed in the master cylinder device.
As is known, when the braking of the vehicle takes place, the vehicle-body load moves forward and is one-sided towards the front wheels rather than being equally distributed between the front and rear wheels. It is therefore desirable to distribute a braking force depending on this movement of load to the front wheels and rear wheels. For this reason, in the past, a produced liquid pressure from the master cylinder device is directly applied to the front wheels whereas low liquid pressure is applied to the rear wheel brake through a control valve.